Ecological aspects of the operation of the Kiev hydroelectric station in a pumped-storage regime

Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 9, pp. 32–34, September, 1988.     

Increasing the Accuracy of Reproduction of Pressure by Means of the Ukrainian Secondary Standard of the Unit of Pressure

The estimated components of the error in the determination of the effective area of a measuring piston-cylinder assembly of a piston manometer with a non-sealed piston are reported. Such manometers are incorporated into the secondary standard of the unit of pressure.     

Corrosion and stress-corrosion resistance of deposited metals in hydrogen-sulfide solutions

We study the corrosion, electrochemical, and corrosion–mechanical properties of deposited KKh30N6VSR cobalt-based, NKh15SR3 nickel-based, and Kh16N8S5 iron-based alloys in a standard NACE hydrogen-sulfide solution. It is shown that the deposited Kh16N8S5 iron-based alloy is unsuitable for these conditions due to its low corrosion resistance and susceptibility to hydrogen-induced cracking. The cobalt- and nickel-based alloys are suitable for the surfacing of the components of shutoff fittings of the oil-and-gas extraction equipment. However, as far as the “operating characteristics–cost” ratio is concerned, the nickel-based alloy outweighs the cobalt- based alloy.     

Aerodynamic performance of a dual turbine concept characterized by a relatively close distance between rotors

In this work, a closely spaced dual turbine concept is studied. The distance between the two side-by-side hubs is 1.05 $D$, where $D$ is the rotor diameter. This configuration has a potential benefit for offshore wind developments in which power density can be maximized. The main goal is to evaluate the overall aerodynamic performance, blade loads, and wake structure of a reference wind turbine generator operating within this dual turbine configuration and to compare the effects against those for the typical single turbine configuration. For this purpose, an actuator line model has been employed together with the large eddy simulation approach for predicting the turbulence effects. This model was implemented by using the open-source computational fluid dynamics toolbox OpenFOAM. Results show a better performance for the dual turbine concept. Under same operating conditions, the aerodynamic power of each turbine within the dual concept is higher than the power of the stand alone turbine, particularly at lower operating wind speeds (approximately 2% to 3% of extra power per turbine). Comparison between the two configurations shows similar character of the tangential and normal forces acting on the blades in terms of magnitude and fluctuation, eliminating potential concerns regarding fatigue and blade design. The largest difference in the tangential and normal root bending moments are approximately 3% and 2%, respectively, between single and dual turbine configurations. Finally, wake recovery analysis shows a downwind velocity deficit that is not enhanced streamwise in the dual turbine configuration with no considerable difference after 7 $D$.